Today, televisions (TVs) have been digitized gradually with the development of digital technology (existing analog televisions have been replaced with digital televisions), and on the one hand, a convergence of broadcasting and communication that provide content having other attributes is accelerating. In other words, the initiative is shifted from unidirectional analog broadcasting to bi-directional digital broadcasting that interacts with the viewers. In addition, available methods that the viewers take advantage of the broadcast content are also diversified, inclusive of receiving the broadcast content through Digital Multimedia Broadcasting, the Internet and the like.
Additionally, T-commerce is already in practical use to implement e-commerce via the television, and additional information such as various goods, locations and the like that are informed through the broadcast content is provided to the viewers in real time. In other words, the viewers can purchase various products and perform financial transaction through the television, and can also acquire information such as goods, locations and the like provided from the broadcast content while watching. For example, a viewer can purchase a good that wishes to buy using an Internet TV, and obtain desired information by directly connecting to URL (Uniform resource Locator) provided along with the broadcast content by use of a DMB receiver.
However, the additional information is typically outputted in an overlapped fashion on the image of the broadcast content that is displayed, which may hinder viewing experience of the broadcast content of the viewer. This is because that the additional information is superimposed on the image displayed on the television or DMB receiver to screen a portion of the displayed image.
In addition, when the viewer wishes to access the URL included in the displayed image, an application such as a web browser is executed in a device to display the broadcast content (for example, a personal computer or a mobile terminal, etc.) to interrupt the viewing experience of the viewer. Of course, it may be possible to split a display screen into a screen on which the broadcast content is displayed and anther screen on which an accessed web page is displayed so as to display both. However, this makes the image of the broadcast content small and thus there still remains a problem such as hindrance of the viewing experience of the viewer. This aforementioned problem has become the main obstacle of the activation of the T-commerce. In other words, as the T-commerce means an e-commerce that utilizes a television or a DMB receiver, the viewing experience of the viewer may be interrupted for the reason described above if the viewer wants to use the e-commerce through the use of the television.
Further, when the viewer watches the broadcast content using an analog television or television that is installed in a public place, the additional information does not be available to the viewer. It is because that the viewer cannot utilize the additional information since the analog television itself cannot receive the additional information, and the viewer cannot handle the additional information even if the additional information can be received through the televisions in a public place.
Furthermore, the viewer should buy the Internet television or the like in order to utilize the relevant additional information while watching the broadcast content, which gives a financial burden to the viewer.
In order to solve these problems, it may be necessary to separate a device through which the viewer watches the broadcast content (for example, a television receiver, a desktop computer, etc.) and another device through which the additional information is provided, and such a separation needs to synchronize the broadcast content and the additional information.
In this regard, a conventional art discloses a method of synchronizing the local times of a broadcast transmitter and a broadcast receiver using a universal time of GPS only during a real time broadcasting (see, U.S. Pat. No. 7,673,316). However, the conventional art has a demerit that it cannot find out automatically whether what kind of content the viewer watches and is not applicable to the content such as an on-demand video or on-demand DVD. That is, the conventional art has a shortcoming that is merely applicable to the broadcast content that is provided from a CP (Content Provider).
Another conventional art discloses a method including receiving an audio sample of a content that a viewer is watching, determining a temporal location within the content of the received audio sample (e.g., an audio fingerprint), detecting additional information corresponding to the temporal location to transmit the addition information to a terminal of a viewer (see, U.S. Patent Publication No. US2011/0063503). However, the conventional art searches the temporal location of the voice sample based on the voice sample received from a remote server, and thus the terminal of the viewer should periodically mutually communicate with the server in order to identify whether the viewer changes the viewing content (e.g., channel shift or skip over the reproducing time, etc.). This consumes a network bandwidth and imposes a load on the server. Although the network bandwidth consumption and/or the load on the server may be relieved by way of lengthening the communication time period between the server and the viewer terminal, it may cause another issue that the conventional art cannot sensitively respond to the change in the content viewing of the viewer.